Intranasal Ketamine for Episodic Neuropathic Pain in a Cancer Patient: A Case Report

<b><i>Background:</i></b> Ketamine is an N-methyl-D-aspartate receptor antagonist traditionally used for dissociative sedation that has also been used for the treatment of pain. Ketamine can have a higher bioavailability when administered intranasally. <b><i>Objective:</i></b> To present a case in which intranasal (IN) ketamine was used for unpredictable, episodic, cancer-related neuropathic pain. <b><i>Case Presentation:</i></b> We present a 49-year-old patient with metastatic adenocarcinoma of the lung who presented to our outpatient palliative care clinic with uncontrolled severe episodic neuropathic pain of the lower extremity. <b><i>Case Management:</i></b> We prescribed compounded racemic ketamine 20-30 mg intranasally as needed at the onset of severe episodes of breakthrough pain, in addition to scheduled use of oral methadone and a buprenorphine patch for long-acting pain management. <b><i>Case Outcome:</i></b> The patient reported a decrease in frequency, intensity, and duration of episodic breakthrough pain with use of IN ketamine without any reported negative adverse effects. <b><i>Conclusion:</i></b> Low-dose compounded racemic IN ketamine may be a useful and safe adjunct in alleviating severe breakthrough pain in cancer patients in the outpatient setting.